1. Technical Field
The present disclosure generally relates to electronic design automation. More specifically, the present disclosure relates to modeling electron-beam (e-beam) proximity effects during e-beam lithography, and correcting a mask layout to compensate for the e-beam proximity effects.
2. Related Art
Rapid advances in computing technology have made it possible to perform trillions of computational operations each second on data sets that are sometimes as large as trillions of bytes. These advances can be attributed to the dramatic improvements in semiconductor manufacturing technologies which have made it possible to integrate tens of millions of devices onto a single chip.
Conventional photolithography processes are close to reaching their physical limit in terms of the minimum feature size that can be printed with these technologies. Hence, the semiconductor industry is actively considering various next-generation photolithography technologies which will enable feature sizes to be miniaturized even further. One of the more promising technologies is electron-beam (e-beam) lithography. It has emerged as one of the leading technologies for manufacturing devices directly on wafer (i.e., e-beam direct write) when the critical dimensions shrink to below 20 nm and mask cost becomes prohibitively high. In both cases, patterning fidelity is compromised by some undesirable electron effects, such as beam blurring, primary electron forward scattering and backscattering, secondary electron scattering, fogging, and resist heating and charging, among others.
Process models are commonly used to model semiconductor manufacturing processes. A process model can be used in a number of applications during the design of a semiconductor chip. For example, process models are commonly used for making corrections to layouts to compensate for undesirable effects of semiconductor manufacturing processes.
Inaccuracies in the process model can negatively affect the efficacy of downstream applications. For example, inaccuracies in a photolithography process model can reduce the efficacy of optical proximity correction (OPC). Hence, it is desirable to develop accurate process models for next-generation process technologies.